Polyarylene sulfide foams and a process for their production

Abstract

A foamed polyarylene sulfide according to the invention has a density which is reduced by at least 50% compared with the theoretical density of nonfoamed material, and is expediently produced by subjecting a polyarylene sulfoxide as such or a mixture of one or more polyarylene sulfides with a polyarylene sulfoxide to heat treatment. The temperature of the heat treatment is in the range from 250° to 400° C.

We claim: 
     
       1. A foamed polyarylene sulfide produced by the process which comprises heating at least one polyarylene sulfoxide or a mixture comprising one or more polyarylene sulfides and at least one polyarylene sulfoxide at a temperature in the range from 250° to 400° C. to obtain a foamed polyarylene sulfide having a density which is decreased by at least 50% as compared to the density, determined prior to said heating step, of said polyarylene sulfoxide or said mixture. 
     
     
       2. A foamed polyarylene sulfide as claimed in claim 1, wherein the foam structure of said foamed polyarylene sulfide is open-pored. 
     
     
       3. A method of producing a molded article comprising the step of molding a foamed polyphenylene sulfide of claim 1. 
     
     
       4. A molded, foamed article produced by the process of claim 3. 
     
     
       5. A molded, foamed article produced by the process comprising: heating at least one polyarylene sulfoxide or a mixture comprising one or more polyarylene sulfides and at least one polyarylene sulfoxide to a temperature in the range of 250° to 400° C.; obtaining a polyarylene sulfide foam as a result of said heating step; and molding the resulting polyarylene sulfide foam into a molded article.